Lipid interactions in the presence of ATP molecules

POSTER

Abstract

Lipids are molecules found in biological cells containing one hydrophilic and one hydrophobic section. When immersed in water, they form multilamellar membrane structures with a regular lattice spacing (D-spacing) on the order of 5 to 15 nm. The equilibrium spacing of membranes is determined by a balance of forces that include van der Waals and electrostatics and it depends on the composition of the aqueous solution in which membranes are formed. In this work, we have used x-ray scattering and NMR spectroscopy to study how lipid interactions are modified in the presence of adenosine triphosphate (ATP) which is the molecule involved in energy transfer in biological systems. In certain environments, such as low pH, ATP has the potential to be highly charged. We find that ATP can attach to membranes and drastically increase the lattice spacing of multilamellar membrane structures. The most likely mechanism is that ATP enhances the electrostatic repulsion of neighboring membranes and at the same time it reduces their van der Waals attraction by changes in dielectric properties of the aqueous solution. Knowledge of the physical mechanism of ATP interacting with membranes can help better understand biological processes at the lipid-water interface.

Authors

  • Ryan Z. Lybarger

    IUPUI Department of Physics, Indianapolis, IN

  • Matt Bowers

    University of Notre Dame, University of Bari, Gran Sasso Science Institute, JINA and UND, UTK, LLNL, OU, INFN, TAMU, Universidad Complutense, Madrid, Lawrence Livermore National Laboratory, Division of Nuclear Physics, National Centre for Nuclear Research, Warsaw, Notre Dame University, University of Michigan, Michigan State University, Univ of Notre Dame, Weizmann Institute, Univ of Birmingham, Univ of Michigan, Oak Ridge National Laboratory, Argonne National Laboratory, The Hebrew University Jerusalem, Indiana University Purdue University Fort Wayne, Professor, University of Notre Dame, Assistant Professor, University of Notre Dame, PhD student, Associate Professor, University of Notre Dame, University of Richmond, University of Surrey, University of Richmond, University of Oslo, University of Wisconsin-La Crosse, University of Notre Dame, Department of Civil Engineering, University of Notre Dame, Department of Applied Computational Mathematics and Statistics, IUPUI Department of Physics, Indianapolis, IN, Ohio Northern University, Northern Kentucky University, Physics Department, Unversity of Missouri, Physics Department, REU Summer Intern, Sichuan University, Purdue University, Princeton University, Monmouth College, ETH, Switzerland, EPFL, Switzerland, Institut Laue-Langevin, France, Kent State University, University of Tennessee, Indiana University South Bend, University Of Notre Dame

  • Horia I. Petrache

    Indiana University Purdue University Indianapolis, IUPUI Department of Physics, Indianapolis, IN